Alpha-Thalassemia

Baby Detect > Haematology > Alpha-Thalassemia

HBA1 and HBA2 genes

OMIM#604131 https://omim.org/entry/604131

1. The disease:

A rare inherited hemoglobinopathy characterized by impaired synthesis of two to all four alpha-globin chains leading to a variable clinical picture depending on the number of affected alleles.

2. The symptoms:

Disease expression varies according to the level of alpha-globin chain deficiency. Lack of early signs or symptoms does not exclude the diagnosis.  

  • Alpha-thalassemia 2 or alpha+-thalassemia causes mild anemia (often detected on routine blood tests), generally with no other symptoms.
  • Alpha-thalassemia 1 or alpha0-thalassemia can present as the most severe form Hb Bart’s hydrops fetalis involves a severe deficiency in alpha-globin chains with serious developmental implications.
  • A combination of the molecular basis of alpha-thalassemia 2 and alpha-thalassemia 1 can cause Haemoglobin H disease (HbH), which is characterized by moderate hemolytic anemia with variable amounts of hemoglobin H along with occasionally severe splenomegaly, sometimes complicated by hypersplenism and necessity of transfusions.

3. Actions to take in case of early diagnosis:

  • Correlation with other exams as hematologic testing of red blood cell (RBC), peripheral blood smear, supravital stain to detect RBC inclusion bodies, and qualitative and quantitative haemoglobin analysis is important.
  • Alpha-thalassemia is a lifelong disease requiring lifetime management and regular follow-up with a Haematology Center.
  • Specific treatment is required and may include occasional or regular red blood cell transfusions, iron chelation, and other supportive measures.
  • Neonates with Hb Bart’s hydrops fetalis usually have a severe presentation. In patients with haemoglobin H disease, the prognosis is usually good, but depends on complications and care.
  • The pattern of inheritance is autosomal recessive and genetic counselling should be offered to at-risk family members.

4. For more information:

Orphanet : https://www.orpha.net/consor/cgi-bin/Disease_Search.php?lng=EN&data_id=50&Disease_Disease_Search_diseaseGroup=alpha-thalassemia&Disease_Disease_Search_diseaseType=Pat&Disease(s)/group%20of%20diseases=Alpha-thalassemia&title=Alpha-thalassemia&search=Disease_Search_Simple

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